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1.
《中国家禽》2018,(24)
将巴氏杀菌蛋清液在4℃下冷藏0～13 d,测定储藏期间蛋清液起泡性和凝胶性的变化。结果表明:在冷藏期间,蛋清液起泡性先下降后上升,鲜蛋的起泡性为0.691,第9天蛋清液起泡性达到较低值0.283,较鲜蛋样降低59.04%;泡沫稳定性先上升后下降,鲜蛋泡沫稳定性为0.926,冷藏第8天达到较大值0.955,较鲜蛋样增高3.13%;凝胶强度呈波浪式变化,鲜蛋液凝胶强度为935.095 g/cm~2,第4天达到较低值540.282 g/cm2,较鲜蛋样降低42.22%,第11天达到较大值1 408.763 g/cm~2,较鲜蛋样增加50.65%;凝胶弹性也呈波浪式变化,第5天和第10天凝胶弹性较大,分别为1.579和1.908。由此可知,蛋品加工若要利用起泡性,不应将蛋清液冷藏;若要利用泡沫稳定性,需在4℃适当冷藏,并综合考虑其起泡性;若要利用凝胶强度,应在4℃冷藏11 d后再进行加工;利用凝胶弹性需在4℃冷藏5或10 d。 相似文献
2.
研究通过监测不同温度(25℃、4℃)储藏鸡蛋蛋液pH值、起泡性和泡沫稳定性随时间的变化,分析储藏时间对蛋清液起泡性的影响。结果显示:鲜蛋于常温25℃条件下放置29 d,全蛋液p H值先由6.8升至7.7后逐渐降低,蛋清液起泡性随储藏时间的延长先升高后降低,起泡性初始值为107.8%,储藏25 d后达到421.2%,之后逐渐降低;4℃下储藏的样品起泡性变化规律与常温相似,储藏17 d后达到270.9%。研究表明:在使用鸡蛋生产焙烤食品时,选用4℃储藏2周或25℃储藏1周的鸡蛋较好。 相似文献
3.
《中国家禽》2020,(7)
为最大限度提高全蛋液的乳化性,以全蛋液为研究对象,进行单因素及响应面试验,对乳化性专用全蛋液超声杀菌工艺条件进行优化。在保证微生物致死率大于90%的条件下,优化乳化性专用全蛋液的超声功率(130～390 W)与处理时间(10～30 min)。结果显示:随超声功率增大和时间延长,乳化性先增大后减小,分别在超声功率为260 W和超声时间为20 min时达到较大值(1.455和1.456)。考虑到实际生产和响应面结果,较优工艺参数为超声功率278 W、处理时间19 min,在此条件下,乳化性为1.486,较未经处理全蛋液的乳化性提高3.6%,较巴氏杀菌蛋液的乳化性高7.07%。研究表明:超声波杀菌较巴氏杀菌更适宜生产乳化性专用全蛋液。 相似文献
4.
为分析冷鲜猪肉贮藏期间微生物污染对其品质的影响,从规模化生猪屠宰场,随机抽取10头猪后腿肉,于4℃冷藏。将每头猪肉样品平均分为11份,分别于0～10 d进行感官评价以及菌落总数和挥发性盐基氮测定。结果显示:0～3 d,菌落总数、挥发性盐基氮含量均不超标,冷鲜猪肉品质保持良好;4～6 d,猪肉品质开始降低,但绝大部分仍为近似鲜品;7 d以后,猪肉品质迅速降低,逐步腐败变质。结果表明,冷鲜猪肉贮藏期间,微生物污染对其品质有很大影响,在4℃冷藏条件下,冷鲜猪肉在3 d内能够保持良好品质。 相似文献
5.
为研究真空包装冷鲜牛肉在0~4℃贮藏期间的品质变化规律,对贮藏期间冷鲜牛肉汁液流失、p H值、菌落总数、挥发性盐基氮(TVB-N)、色差值(a*)、蒸煮损失等指标进行定期测定。结果表明:在贮藏期间,冷鲜牛肉失重率增加,p H值呈先上升后下降再上升趋势,菌落总数和TVB-N均呈增加趋势,红度值a*先上升后下降,蒸煮损失增大。结合菌落总数和TVB-N,真空包装冷鲜牛肉的货架期为21d。 相似文献
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7.
《中国畜牧杂志》2015,(12)
为探讨冷鲜鸡肉品质变化规律,选择42日龄快大型AA肉鸡(文中简称"白鸡")与126日龄优质型梅岭土鸡(文中简称"黄鸡")各72只,宰后于0~4℃冷鲜保藏,并于贮藏第0~5d分别采样测定鸡胸肉的pH值、剪切力、挥发性盐基氮、TPA质构值、肌苷酸等理化指标。结果发现,随着贮藏时间的延长,冷鲜鸡的pH值、挥发性盐基氮呈上升趋势,剪切力降低。0~4℃冷鲜保藏5d,鸡肉品质逐渐下降,但新鲜度指标仍在国家标准允许范围之内;真空包装的保鲜效果更理想。优质黄鸡相对于白鸡而言,某些指标表现出耐贮藏的特性,但其剪切力、肌苷酸含量等特色值下降较快,为此应及早销售以体现其肉质风味优势。 相似文献
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9.
采用常温、干燥、超干、冷藏、冷冻5种不同的贮藏方法,测定处理30、90d燕麦种子活力及抗氧化酶指标,结果表明:(1)低温贮藏促进燕麦根、苗的生长,最大分别达到9.11cm和13.946cm;(2)种子贮藏90d后,种子活力差异显著,发芽率、发芽指数均在超干贮藏条件下达到最大,为91.33%和81.211,显著高于其他贮藏方法,此时种子的电导率显著低于其他贮藏方法;(3)燕麦种子含水量达到4.53%时,种子活力最高,抗氧化酶活性也较高,种子内SOD、POD、CAT活性达到最大值,分别为0.794、199.56、19.97U/(g·min)FW。5种不同贮藏方法中,对短期贮藏燕麦种子的优势表现为:超干贮藏干燥贮藏常温贮藏冷藏贮藏冷冻贮藏。 相似文献
10.
正据《食品科学》2012年第7期《基于电子鼻技术对冷藏后南果梨货架期间气味的变化分析》(作者纪淑娟等)报道,采用电子鼻技术检测直接冷藏和经1-甲基环丙烯(1-MCP)处理后冷藏的南果梨在常温(20℃)货架期间挥发性物质的变化,分析直接冷藏和1-MCP处理再冷藏的南果梨挥发性物质的变化规律,并探讨电子鼻应用于检测南果梨挥发性物质的可能性。采用主成分分 相似文献
11.
为探讨夏季常温保存和低温冷藏两种储藏方式对鸡蛋品质的影响,选择540个鸡蛋随机分为9组,1组当天测定蛋品质,3组置于28.31 ℃、湿度为68.13%的室温下保存,5组置于4~8 ℃的冷藏室保存,分别于第7、14、21、42和56 d测定蛋品质。结果表明,常温储藏的鸡蛋随着存放时间延长,鸡蛋品质不断下降,储藏21 d后,蛋重降低5.30%（P<0.05）,蛋壳厚度变薄（P<0.05）;哈氏单位随着储藏时间的延长迅速下降,第0 d比第21 d的哈氏单位值高59.18%（P<0.05）;蛋黄比率随储藏时间的延长有不断变大的趋势,第0 d的蛋黄比率比第21 d低15.58%（P<0.05）。低温冷藏的鸡蛋储藏到21 d时,仅哈氏单位比第0 d低6.78%（P<0.05）;冷藏到56 d时,蛋重和哈氏单位比第0 d分别降低5.63%和15.07%（P<0.05）,蛋黄比率提高了5.21%（P<0.05）。试验表明,鸡蛋在室温下的新鲜度适宜保存期不应超过21 d;低温冷藏时可以保存到56 d。 相似文献
12.
Naoi H Otoi T Shimamura T Karja NW Agung B Shimizu R Taniguchi M Nagai T 《The Journal of reproduction and development》2007,53(2):271-277
We conducted two experiments to investigate the effects of storage temperature and period for cat ovaries on the meiotic and developmental competence of oocytes collected from the ovaries. In Experiment 1, ovaries were stored in physiological saline for 24 h at 4 C, 23-25 C, or 38 C (cold, room, and incubator temperature groups, respectively), and then oocytes were collected from the ovaries in each group. Morphologically intact oocytes were then selected and cultured in maturation medium for 24 h. Significantly more oocytes reached metaphase II (MII) in the cold temperature group (53.4%) than in the room and incubator temperature groups (20.0 and 2.4%, respectively). In Experiment 2, ovaries were stored in physiological saline at room temperature for 0, 6, 12 or 18 h, and then they were stored at 4 C (cold storage) until reaching a total storage period of 24 h. After storage of the ovaries, morphologically intact oocytes were matured, fertilized with frozen-thawed spermatozoa, and cultured in vitro. The rates of morphologically intact oocytes obtained from the ovaries stored at room temperature for 0, 6, 12 or 18 h were 35.3, 30.0, 26.4 and 14.7%, respectively, and the rates of intact oocytes that reached MII were 63.2, 36.4, 26.5 and 11.9%, respectively. The results suggested that the numbers of morphologically intact oocytes and intact oocytes that reached MII after in vitro maturation decrease gradually as the period of storage at room temperature before cold storage increases. Only oocytes from ovaries stored for 6 h developed to the blastocyst stage after in vitro maturation and fertilization when ovaries were stored at room temperature before cold storage. These results indicate that 24 h storage of ovaries at high temperatures (>23 C) decreases the meiotic competence of oocytes. The quality and developmental competence of oocytes are influenced by the length of storage at room temperature before cold storage. 相似文献
13.
环境温度和湿度对蛋鸡粪便含水率、氮素和pH的影响 总被引：1，自引：0，他引：1
为了研究温度、湿度因子对存放期蛋鸡粪便含水率和氮素变化的影响,试验在人工气候箱内采用单因素试验设计,分别研究存放0~6d在15、20、25、30℃的温度水平和65%、75%、85%、95%的湿度水平下蛋鸡粪便的成分特性变化。结果表明,在不同环境温度下,0~6d内随着时间延长,蛋鸡粪便含水率均下降;最初1~2d内含水率变化较小,从第3天开始,高温环境(35℃)贮放粪便不利于含水率的降低。环境温度越高,12h~4d粪便pH值上升越快;高温(35℃)会加快粪便降解和氮素损失,而在25℃环境下,环境湿度对存放期粪便的含水率、pH值以及氮素变化没有显著影响。 相似文献
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15.
T. G. Carter 《British poultry science》1972,13(4):341-355
Experiments are described from which it is concluded that the shell will split when an egg is boiled if thermal expansion of the egg's liquid or gaseous contents, which have a higher coefficient of expansion than the shell, is insufficiently relieved by escape through the membranes and pores. The probability of splitting was enhanced if the shell had low structural strength due to a pre‐existing crack or to large size, skew shape or low effective thickness; once these factors had been taken into account there was no significant effect of the shell's aspect ratio, colour, glossiness, roughness or degree of ridging, nor of the hen's age or a strain history of selection for egg production. The incidence of splitting depended also on storage time and temperature: it was very low in newly laid eggs; in eggs stored at room temperature it rose to a maximum at about 5 d, then fell and was again low after about 21 d; in eggs stored at — 2 °C the time‐scale was increased and the incidence of splitting was still high after 14 d storage. These effects are due to two changes occurring during storage: progressive reduction of permeability of the membranes and shell to the liquid contents of the egg, which impedes escape of the contents when they expand during cooking, and progressive increase in the size of the air space, which provides expansion space. Allowing refrigerated eggs to warm to room temperature before cooking and adding salt to the cooking water did not significantly affect the incidence of splitting; putting eggs into cold rather than boiling water did not reduce the incidence of splitting except when the air space was large, following prolonged storage at room temperature.
The belief, common among housewives, that shell splitting occurs more commonly now than in earlier decades may be well‐founded but, if so, the change is probably due to a combination of two practices that have been introduced to maintain interior egg quality but which coincidentally raise the probability of shell‐splitting during boiling: rapid distribution from hen to housewife and refrigerated storage. There is no evidence that shells are now thinner, that hens of modern, high‐production strains lay eggs with weaker shells or that white shells are weaker than brown ones. 相似文献
16.
1. The aim of this study was to investigate the stability of immunoglobulin-Y (IgY) in stored eggs from immunised hens. 2. Eggs from individual hens were randomised and stored for up to one month at room temperature, or for up to 6 months at +4°C. IgY was extracted from the egg yolks and the antibody activities were tested by ELISA. 3. There was no significant reduction in antibody titres with egg storage under these conditions. 4. Egg yolks of immunised chickens provide an inexpensive source of large amounts of polyclonal antibodies for use in immunotherapy and immunoassays. By collecting eggs from different immunised hens and pooling their yolks, it should be possible to reduce batch-to-batch variation. 相似文献
17.
Tsutsui T Tezuka T Mikasa Y Sugisawa H Kirihara N Hori T Kawakami E 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2003,65(3):307-312
Cooled canine semen solutions for storage were investigated with three stock solutions: egg yolk-citrate-glycine-glucose solution, egg yolk Tris-fructose citrate solution (EYT-FC), and egg yolk sodium citrate dihydrate solution (EYCD). For the control group, the second fraction of semen was examined. Nine male beagles and 37 female (47 experimental cases) beagles for artificial insemination (AI) were used. The qualities of semen stored at 4 degrees C deteriorated earlier in the control and EYCD groups. In the other two groups, sperm motility was 60% or higher after storage for 6 days and 20% or higher after storage for 12 days. On a comparison of these two groups, the sperm motility and viability were slightly higher in the EYT-FC group. A high conception rate was obtained by AI using semen stored at a low temperature for a maximum of two days in the control group and four days in the EYT-FC group. 相似文献
18.
OBJECTIVE: To investigate the effects of storage duration and temperature on haematological analyses performed on blood from the western grey kangaroo (Macropus fuliginosis). METHOD: Blood samples from five western grey kangaroos were stored at 4 degrees C, 24 degrees C and 36 degrees C. Each sample was analysed haematologically over a 5-day period. RESULTS: The blood samples maintained optimal stability at 4 degrees C. At this temperature the haematological values remained essentially unchanged for the duration of the study, while samples stored at 36 degrees C and 24 degrees C showed significant changes in some haematological measures by 12 h and 48 h, respectively. Disturbances in leukocyte morphology were evident, to varying degrees, in all samples. CONCLUSIONS: Blood samples from macropodids should be tested within 48 h of collection if stored at a room temperature of about 24 degrees C. Where testing is to be delayed for more than 48 h, samples should be refrigerated as soon as possible. Exposure of samples to heat in excess of 24 degrees C should be avoided at all times. 相似文献
19.
为了探究不同贮藏温度对市售热鲜牛肉新鲜度的影响，试验以市售热鲜牛肉为研究对象（采自4头锦江黄牛背最长肌），测定其在不同贮藏温度（5、15、25和35℃）和相对湿度（relative humidity，RH）为80%条件下，pH、L*、a*、b*值、菌落总数、硫代巴比妥酸（thiobarbituric acid reactive substances，TBARS）和挥发性盐基氮（total volatile basic nitrogen，TVB-N）含量随贮藏时间（0、6、12、24、48、72、96和120 h）的变化情况。结果表明，随着贮藏时间延长，不同贮藏温度处理组热鲜牛肉的pH均呈先降低后上升的趋势，L*、a*和b*值呈先上升后降低趋势，菌落总数、TBARS和TVB-N含量呈上升趋势；且贮藏温度越高，各指标随时间变化的趋势加剧。综合分析各指标的变化规律，为了保证热鲜牛肉的新鲜度和食用安全性，在5、15、25和35℃下贮藏的热鲜牛肉，其货架期分别不能超过96、72、24和12 h。 相似文献
20.
保存温度和不同种类稀释液对猪精液品质的影响 总被引：2，自引：0，他引：2
猪精液在室温保存时,含庆大霉素的稀释液保存效果优于含青、链霉素的稀释液,两种稀释液在保存72h时,精子活率、顶体完整率、GOT和LDH活性以及存活指数差异极显著(P<0.01).低温保存时,含蜂蜜和卵黄的稀释液对防精子冷刺激、维持精子活率的效果比含葡萄糖、奶粉的稀释液理想.在冷冻保存条件下,以含2%甘油的稀释液保存效果最佳.液态保存(室温、低温)的猪精液,LDH活性随精子活率下降而下降;pH值则都呈先上升后下降的变化趋势.室温保存主要是引起精子顶体脊膨大和保存后期的顶体前端膨大;低温保存主要引起顶体前部膨大和保存后期的少数顶体脱落;冷冻保存主要是造成顶体的膨大程度加大和顶体脱落.3种保存条件都造成精子线粒体透性增强.液态保存和冷冻保存精液的精清GOT活性与顶体完整率无显著相关性(P>0.05). 相似文献